Functionalized ceramics for hydrogenotrophic biomethanation

The production of biomethane offers the possibility of converting organic waste materials into a gaseous, easily storable energy carrier with a high energy density. To meet the required quality standards for injecting biomethane into the established gas storage grid, contaminants—primarily CO₂—must be removed. The CO₂ separated from the raw biogas or digester gas can then be used as a feedstock for additional methanation with renewable hydrogen to maximize the achievable injection volume. A widespread implementation of such a circular-economy CCU approach has so far not been realized due to excessively high investment and operating costs as well as the persistent dominance of fossil energy sources. As the expansion of cost-efficient, variable renewable energy progresses, a future seasonal balancing demand in the double-digit terawatt-hour range is expected. Biomethanation could therefore enable the methanation of hard-to-abate CO₂ sources (e.g., from wastewater treatment plants) during periods of electrical overcapacity, which would on the one hand result in negative emissions and on the other hand produce a storable energy carrier. The project “BioCH4eramics” aims to establish the foundation for a radically new type of bioreactor (“plug-flow”) and a new biotechnological process for the production of biomethane. By specifically immobilizing methanogenic microorganisms within the pore space of technical ceramics, the use of the plug-flow reactor with a large specific surface area as a potentially highly efficient production system for biomethane will be experimentally investigated.